{"id":1252852,"date":"2026-03-01T13:57:07","date_gmt":"2026-03-01T13:57:07","guid":{"rendered":"http:\/\/ByL8nHhUeqxBSbDyaWNtuJ"},"modified":"2026-03-01T13:57:07","modified_gmt":"2026-03-01T13:57:07","slug":"crucial-128-gb-ddr5-6400-cudimm-review","status":"publish","type":"post","link":"https:\/\/arcader.org\/news\/crucial-128-gb-ddr5-6400-cudimm-review\/","title":{"rendered":"Crucial 128 GB DDR5-6400 CUDIMM review"},"content":{"rendered":"
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With its Core Ultra 200S<\/a> range of processors, Intel became the first CPU manufacturer to support CUDIMMs (Clocked Unbuffered Dual Inline Memory Modules). Essentially just standard RAM sticks, each one sports a tiny module called a client clock driver<\/em> (CKD for short) that boosts the signal to ensure it remains stable at very high clock speeds.<\/p>\n

The first round of CUDIMMs, such as Corsair’s Vengeance DDR5-8400<\/a> set, went down the performance route, but there is an alternate use of the CKD. Rather than keeping things nice and clean at high speeds, it can do the same for when a DIMM is loaded to the hilt with memory chips.<\/p>\n

That’s exactly what Crucial has done with its 128 GB DDR5-6400 kit, with two sticks of 64 GB running at 6,400 MT\/s. Since Intel’s Arrow Lake processors natively support that speed with CUDIMMs, the kit doesn’t sport any XMP or EXPO profiles. In other words, you can’t overclock them or use Intel’s 200S Boost mode<\/a> for more gaming performance (as it requires an XMP profile to be present).<\/p>\n

Well, you can try,<\/em> and I’ll come back to that later. For now, it’s simply a case of dropping them into your Z890 or B850 motherboard, and away you go with 128 GB of RAM.<\/p>\n

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Crucial 128 GB DDR5-6400 CUDIMM specs<\/div>\n
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\"A<\/p>\n<\/div>\n<\/div>

(Image credit: Future)<\/span><\/figcaption><\/figure>\n

RAM type:<\/strong> DDR5 CUDIMM
Chipset support:<\/strong> Intel 800 series (CUDIMM mode)
DIMM capacity:<\/strong> 64 GB each (128 GB kit)
Base speed:<\/strong> 6,400 MT\/s
Base latencies:<\/strong> 52-52-52-103
Base voltage:<\/strong> 1.1 V
Overclocked profiles:<\/strong> None
Overclocked speed:<\/strong> N\/A
Price: <\/strong>$468<\/a><\/p>\n<\/div>\n<\/div>\n

Except it wasn’t that easy at all. The first motherboard I tested the kit with was ASRock’s Z890 Taichi Lite<\/a>, which clearly states that the Crucial memory kit is supported in its RAM QVL (quality vendor list). However, despite my best efforts, the test rig was never stable enough to complete any benchmark, so I turned to an MSI MAG Z890 Tomahawk WiFi<\/a> motherboard, to instant success.<\/p>\n

Interestingly, MSI doesn’t mention the Crucial set in its memory QVL, but there’s clearly something going on with ASRock’s BIOS settings that the CUDIMMs don’t like.<\/p>\n

It’s perhaps something to do with the RAM kit’s timings because 52-52-52-103 are some of the slowest figures I’ve seen in a long time. The good thing about using a CAS latency of 52 cycles, for example, is that the memory will be as stable and reliable as possible.<\/p>\n

The downside is that such a latency equates to a column address strobe (CAS) access time of a little over 16 milliseconds. By comparison, a typical gaming kit of DDR5-6000 CL32 will be just under 11 milliseconds. That might sound very close, but it means the Crucial set is taking 45% longer to read the contents of the RAM after the instruction has been sent.<\/p>\n

Any application that’s sensitive to data speed will certainly not like this, especially since data latency isn’t one of Arrow Lake’s strengths. One such example, of course, is a 3D game, and although Crucial is absolutely not<\/em> aiming the kit at gamers, there are plenty of folks out there who use the same PC for work and gaming.<\/p>\n

Additionally, flight sim enthusiasts will know of certain cases, such as MSFS 2024, where loading up on RAM does make a difference<\/a>, even above 64 GB.<\/p>\n

Benchmarks and performance<\/span><\/h3>\n
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\"A<\/p>\n<\/div>\n<\/div>

The CKD is a tiny, but important, addition. <\/span>(Image credit: Future)<\/span><\/figcaption><\/figure>\n

To highlight the relative strengths and weaknesses of a RAM kit, one needs to isolate the benchmarks from any factors that will influence the results in the same way. To that end, I used a Core Ultra 9 285K<\/a> with a GeForce RTX 4080 Super<\/a>, across three games at 1080p with DLSS Balanced enabled, to minimise the GPU impact.<\/p>\n

For the sake of comparison, I’ve also tested three other memory kits in the same test system: a 96 GB Corsair Vengeance DDR5-6000 CL30<\/a> kit, a 48 GB Corsair Dominator Titanium DDR5-7200 CL36<\/a> kit and a 32 GB set of Lexar Thor OC DDR5-6000 CL32<\/a>. Each kit was tested with the Z890 motherboard set to Intel’s default Arrow Lake profile.<\/p>\n